CSIQ, SCTY, and CLF are making big moves in Thursday's trading

Heading into the final hours of today's session, three of the top market movers are alternative energy concerns Canadian Solar Inc. (NASDAQ:CSIQ) and SolarCity Corp (NASDAQ:SCTY), plus mining company Cliffs Natural Resources Inc (NYSE:CLF). Here's a quick roundup of how this trio of names is performing on the charts so far.

CSIQ is up 4.2% today to linger near $29.72, after this morning entering an Engineering, Procurement, and Construction (EPC) agreement with Kingston Solar LP for the construction of a 40 megawatt (MW) DC (100 MW AC) utility-scale solar energy farm in Canada. Call players have responded enthusiastically to the news, picking up contracts at a rate that more than doubles the average intraday norm. Today's preference for calls over puts echoes a longer-term options trend on Canadian Solar Inc., as the equity sports a 20-day International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) call/put volume ratio of 4.77, with nearly five times as many calls as puts being bought to open during the last month. Elsewhere, short interest increased by more than 35% during the last two reporting periods, and now accounts for 10.1% of CSIQ's available float. As such, it is possible some of the recent option bulls are actually short sellers in disguise, hedging against additional upside.

SCTY reached a three-month peak of $72.10 today, and at last check, was trading 2.7% higher at $70.87. Similar to CSIQ, SolarCity Corp saw an 11.7% spike in short interest during the two most recent reporting periods, and now these bearish bets make up more than one-fourth of the equity's available float. Looking back on the charts, SCTY has gained 37.3% since the start of June, and a continuation of this upward trajectory may cause a short-squeeze scenario, which could translate into additional tailwinds.

CLF has surged 3.9% today to $14.93, after the company issued an open letter urging shareholders to reject the slate of directors proposed by Casablanca Capital. Subsequently, Cliffs Natural Resources Inc saw a spike in call volume today, which short sellers -- picking up insurance against more upside -- may have contributed to. Currently, 35.8% of the stock's float is sold short, and it would take roughly nine sessions to cover these bearish bets, at the shares' average daily volume.